From time to time it is necessary for boats to be removed from the water, such as in connection with storage on private davits, for storage at marinas, or for repair efforts such as scraping, painting, hull repair, and the like. This operation may be accomplished in several different ways, such as by the use of a marine railway, a submersible dock-like device that can be lifted out of the water by power equipment, a sling arrangement, and by the use of lift rings. This invention is entirely concerned with the latter option.
Although the use of slings has enjoyed considerable popularity in the past, many marinas and boat manufacturers are moving in the direction of the widespread use of lift ring is used at the prow, and a pair of U-bolts used at the stern of the boat. In this way, a marina having the right equipment can lift a boat out of the water with minimum effort, and can place it directly on a wheeled vehicle, on chocks, or in whatever location is preferred.
Inasmuch as a boat may be quite heavy, it is necessary for the lift ring on the front of the vessel to attach directly to the keel, for decks are not designed for upward pulling forces. Since the underside of the prow of a boat often curves for a distance upwardly away from the keel, it is usually necessary for the lift ring to be located substantially aft of the forwardmost portion of the prow, so that it will be disposed to be connected directly to the turn of the keel, or to the forwardmost horizontal portion of the keel.
The prior art lift rings have been of fixed construction, which means that they have presented a substantial obstacle in a forward area which must necessarily be used for tying up bow lines, and which would have been usable as a clear deck space if this obstacle did not exist. The ordinary fixed lift ring protrudes three inches or so above the deck, which presents a substantial hazard over which a passenger or deck hand may trip. It was for the elimination of this type of hazard, for the making available of additional deck space, and for the simplification of lift ring installation that the present invention was designed.